aboutsummaryrefslogtreecommitdiffstats
path: root/util/datetime/base.h
blob: c43b9775d0e4e3d179c2850b3b27424f0440c587 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
#pragma once

#include "systime.h"

#include <util/str_stl.h>
#include <util/system/platform.h>
#include <util/system/datetime.h>
#include <util/generic/string.h>
#include <util/generic/strbuf.h>
#include <util/generic/ylimits.h>
#include <util/generic/utility.h>
#include <util/generic/typetraits.h>
#include <util/generic/yexception.h>

#include <chrono>

#if defined(__cpp_lib_three_way_comparison)
    #include <compare>
#endif

#include <ctime>
#include <cstdio>
#include <ratio>

#include <time.h>

#ifdef _MSC_VER
    #pragma warning(push)
    #pragma warning(disable : 4244) // conversion from 'time_t' to 'long', possible loss of data
#endif                              // _MSC_VER

// Microseconds since epoch
class TInstant;

// Duration is microseconds. Could be used to store timeouts, for example.
class TDuration;

/// Current time
static inline TInstant Now() noexcept;

/// Use Now() method to obtain current time instead of *Seconds() unless you understand what are you doing.

class TDateTimeParseException: public yexception {
};

const int DATE_BUF_LEN = 4 + 2 + 2 + 1; // [YYYYMMDD*]

constexpr long seconds(const struct tm& theTm) {
    return 60 * (60 * theTm.tm_hour + theTm.tm_min) + theTm.tm_sec;
}

void sprint_gm_date(char* buf, time_t when, long* sec = nullptr);
bool sscan_date(const char* date, struct tm& theTm);

const int DATE_8601_LEN = 21; // strlen("YYYY-MM-DDThh:mm:ssZ") = 20 + '\0'

size_t FormatDate8601(char* buf, size_t len, time_t when);

inline void sprint_date8601(char* buf, time_t when) {
    buf[FormatDate8601(buf, 64, when)] = 0;
}

bool ParseISO8601DateTimeDeprecated(const char* date, time_t& utcTime);
bool ParseISO8601DateTimeDeprecated(const char* date, size_t dateLen, time_t& utcTime);
bool ParseRFC822DateTimeDeprecated(const char* date, time_t& utcTime);
bool ParseRFC822DateTimeDeprecated(const char* date, size_t dateLen, time_t& utcTime);
bool ParseHTTPDateTimeDeprecated(const char* date, time_t& utcTime);
bool ParseHTTPDateTimeDeprecated(const char* date, size_t dateLen, time_t& utcTime);
bool ParseX509ValidityDateTimeDeprecated(const char* date, time_t& utcTime);
bool ParseX509ValidityDateTimeDeprecated(const char* date, size_t dateLen, time_t& utcTime);

bool ParseISO8601DateTime(const char* date, time_t& utcTime);
bool ParseISO8601DateTime(const char* date, size_t dateLen, time_t& utcTime);
bool ParseRFC822DateTime(const char* date, time_t& utcTime);
bool ParseRFC822DateTime(const char* date, size_t dateLen, time_t& utcTime);
bool ParseHTTPDateTime(const char* date, time_t& utcTime);
bool ParseHTTPDateTime(const char* date, size_t dateLen, time_t& utcTime);
bool ParseX509ValidityDateTime(const char* date, time_t& utcTime);
bool ParseX509ValidityDateTime(const char* date, size_t dateLen, time_t& utcTime);

constexpr long TVdiff(timeval r1, timeval r2) {
    return (1000000 * (r2.tv_sec - r1.tv_sec) + (r2.tv_usec - r1.tv_usec));
}

TString Strftime(const char* format, const struct tm* tm);

// Use functions below instead of sprint_date (check IGNIETFERRO-892 for details)
void DateToString(char* buf, const struct tm& theTm);
void DateToString(char* buf, time_t when, long* sec = nullptr);
TString DateToString(const struct tm& theTm);
TString DateToString(time_t when, long* sec = nullptr);
// Year in format "YYYY", throws an exception if year not in range [0, 9999]
TString YearToString(const struct tm& theTm);
TString YearToString(time_t when);

template <class S>
class TTimeBase {
public:
    using TValue = ui64;

protected:
    constexpr TTimeBase(const TValue& value) noexcept
        : Value_(value)
    {
    }

public:
    constexpr TTimeBase() noexcept
        : Value_(0)
    {
    }

    constexpr TTimeBase(const struct timeval& tv) noexcept
        : Value_(tv.tv_sec * (ui64)1000000 + tv.tv_usec)
    {
    }

    constexpr TValue GetValue() const noexcept {
        return Value_;
    }

    constexpr double SecondsFloat() const noexcept {
        return Value_ * (1 / 1000000.0);
    }

    constexpr double MillisecondsFloat() const noexcept {
        return Value_ * (1 / 1000.0);
    }

    constexpr TValue MicroSeconds() const noexcept {
        return Value_;
    }

    constexpr TValue MilliSeconds() const noexcept {
        return MicroSeconds() / 1000;
    }

    constexpr TValue Seconds() const noexcept {
        return MilliSeconds() / 1000;
    }

    constexpr TValue Minutes() const noexcept {
        return Seconds() / 60;
    }

    constexpr TValue Hours() const noexcept {
        return Minutes() / 60;
    }

    constexpr TValue Days() const noexcept {
        return Hours() / 24;
    }

    constexpr TValue NanoSeconds() const noexcept {
        return MicroSeconds() >= (Max<TValue>() / (TValue)1000) ? Max<TValue>() : MicroSeconds() * (TValue)1000;
    }

    constexpr ui32 MicroSecondsOfSecond() const noexcept {
        return MicroSeconds() % (TValue)1000000;
    }

    constexpr ui32 MilliSecondsOfSecond() const noexcept {
        return MicroSecondsOfSecond() / (TValue)1000;
    }

    constexpr ui32 NanoSecondsOfSecond() const noexcept {
        return MicroSecondsOfSecond() * (TValue)1000;
    }

    constexpr explicit operator bool() const noexcept {
        return Value_;
    }

protected:
    TValue Value_; // microseconds count
};

namespace NDateTimeHelpers {
    template <typename T>
    struct TPrecisionHelper {
        using THighPrecision = ui64;
    };

    template <>
    struct TPrecisionHelper<float> {
        using THighPrecision = double;
    };

    template <>
    struct TPrecisionHelper<double> {
        using THighPrecision = double;
    };
}

class TDuration: public TTimeBase<TDuration> {
    using TBase = TTimeBase<TDuration>;

private:
    /**
     * private construct from microseconds
     */
    constexpr explicit TDuration(TValue value) noexcept
        : TBase(value)
    {
    }

public:
    constexpr TDuration() noexcept {
    }

    constexpr TDuration(const struct timeval& tv) noexcept
        : TBase(tv)
    {
    }

    /**
     * TDuration is compatible with std::chrono::duration:
     *   it can be constructed and compared with std::chrono::duration.
     * But there are two significant and dangerous differences between them:
     *   1) TDuration is never negative and use saturation between 0 and maximum value.
     *      std::chrono::duration can be negative and can overflow.
     *   2) TDuration uses integer number of microseconds.
     *      std::chrono::duration is flexible, can be integer of floating point,
     *      can have different precisions.
     * So when casted from std::chrono::duration to TDuration value is clamped and rounded.
     * In arithmetic operations std::chrono::duration argument is only rounded,
     *   result is TDuration and it clamped and rounded.
     * In comparisons std::chrono::duration argument is rounded.
     */
    template <typename T, typename TRatio>
    constexpr TDuration(std::chrono::duration<T, TRatio> duration) noexcept {
        static_assert(
            std::ratio_greater_equal<TRatio, std::micro>::value &&
                (!std::is_floating_point<T>::value || std::ratio_greater<TRatio, std::micro>::value),
            "Extremely likely it is loss of precision, because TDuration stores microseconds. "
            "Cast you duration explicitly to microseconds if you really need it.");

        if (duration.count() < 0) {
            *this = TDuration::Zero(); // clamp from the bottom
        } else {
            if
#if !defined(__NVCC__)
                constexpr
#endif
                /* if [constexpr] */ (std::ratio_greater<TRatio, std::micro>::value || std::is_floating_point<T>::value) {
                // clamp from the top
                using TCommonDuration = std::chrono::duration<typename std::common_type<T, TValue>::type, TRatio>;
                constexpr auto maxDuration = std::chrono::duration<TValue, std::micro>(::Max<TValue>());
                if (std::chrono::duration_cast<TCommonDuration>(duration) >= std::chrono::duration_cast<TCommonDuration>(maxDuration)) {
                    *this = TDuration::Max();
                    return;
                }
            }
            const TValue us = std::chrono::duration_cast<std::chrono::duration<TValue, std::micro>>(duration).count();
            *this = TDuration::MicroSeconds(us);
        }
    }

    static constexpr TDuration FromValue(TValue value) noexcept {
        return TDuration(value);
    }

    static constexpr TDuration MicroSeconds(ui64 us) noexcept {
        return TDuration(us);
    }

    /* noexcept(false) as conversion from T might throw, for example FromString("abc") */
    template <typename T>
    static constexpr TDuration MilliSeconds(T ms) noexcept(false) {
        return MicroSeconds((ui64)(typename NDateTimeHelpers::TPrecisionHelper<T>::THighPrecision(ms) * 1000));
    }

    using TBase::Days;
    using TBase::Hours;
    using TBase::MicroSeconds;
    using TBase::MilliSeconds;
    using TBase::Minutes;
    using TBase::Seconds;

    /// DeadLineFromTimeOut
    inline TInstant ToDeadLine() const;
    constexpr TInstant ToDeadLine(TInstant now) const;

    static constexpr TDuration Max() noexcept {
        return TDuration(::Max<TValue>());
    }

    static constexpr TDuration Zero() noexcept {
        return TDuration();
    }

    /* noexcept(false) as conversion from T might throw, for example FromString("abc") */
    template <typename T>
    static constexpr TDuration Seconds(T s) noexcept(false) {
        return MilliSeconds(typename NDateTimeHelpers::TPrecisionHelper<T>::THighPrecision(s) * 1000);
    }

    static constexpr TDuration Minutes(ui64 m) noexcept {
        return Seconds(m * 60);
    }

    static constexpr TDuration Hours(ui64 h) noexcept {
        return Minutes(h * 60);
    }

    static constexpr TDuration Days(ui64 d) noexcept {
        return Hours(d * 24);
    }

    /// parses strings like 10s, 15ms, 15.05s, 20us, or just 25 (s). See parser_ut.cpp for details
    static TDuration Parse(const TStringBuf input);

    static bool TryParse(const TStringBuf input, TDuration& result);

    // note global Out method is defined for TDuration, so it could be written to IOutputStream as text

    template <class T>
    inline TDuration& operator+=(const T& t) noexcept {
        return (*this = (*this + t));
    }

    template <class T>
    inline TDuration& operator-=(const T& t) noexcept {
        return (*this = (*this - t));
    }

    template <class T>
    inline TDuration& operator*=(const T& t) noexcept {
        return (*this = (*this * t));
    }

    template <class T>
    inline TDuration& operator/=(const T& t) noexcept {
        return (*this = (*this / t));
    }

    TString ToString() const;
};

Y_DECLARE_PODTYPE(TDuration);

template <>
struct THash<TDuration> {
    size_t operator()(const TDuration& key) const {
        return THash<TDuration::TValue>()(key.GetValue());
    }
};

/// TInstant and TDuration are guaranteed to have same precision
class TInstant: public TTimeBase<TInstant> {
    using TBase = TTimeBase<TInstant>;

private:
    /**
     * private construct from microseconds since epoch
     */
    constexpr explicit TInstant(TValue value) noexcept
        : TBase(value)
    {
    }

public:
    constexpr TInstant() noexcept {
    }

    constexpr TInstant(const struct timeval& tv) noexcept
        : TBase(tv)
    {
    }

    static constexpr TInstant FromValue(TValue value) noexcept {
        return TInstant(value);
    }

    static inline TInstant Now() {
        return TInstant::MicroSeconds(::MicroSeconds());
    }

    using TBase::Days;
    using TBase::Hours;
    using TBase::MicroSeconds;
    using TBase::MilliSeconds;
    using TBase::Minutes;
    using TBase::Seconds;

    static constexpr TInstant Max() noexcept {
        return TInstant(::Max<TValue>());
    }

    static constexpr TInstant Zero() noexcept {
        return TInstant();
    }

    /// us since epoch
    static constexpr TInstant MicroSeconds(ui64 us) noexcept {
        return TInstant(us);
    }

    /// ms since epoch
    static constexpr TInstant MilliSeconds(ui64 ms) noexcept {
        return MicroSeconds(ms * 1000);
    }

    /// seconds since epoch
    static constexpr TInstant Seconds(ui64 s) noexcept {
        return MilliSeconds(s * 1000);
    }

    /// minutes since epoch
    static constexpr TInstant Minutes(ui64 m) noexcept {
        return Seconds(m * 60);
    }

    /// hours since epoch
    static constexpr TInstant Hours(ui64 h) noexcept {
        return Minutes(h * 60);
    }

    /// days since epoch
    static constexpr TInstant Days(ui64 d) noexcept {
        return Hours(d * 24);
    }

    constexpr time_t TimeT() const noexcept {
        return (time_t)Seconds();
    }

    inline struct timeval TimeVal() const noexcept {
        struct timeval tv;
        ::Zero(tv);
        tv.tv_sec = TimeT();
        tv.tv_usec = MicroSecondsOfSecond();
        return tv;
    }

    inline struct tm* LocalTime(struct tm* tm) const noexcept {
        time_t clock = Seconds();
        return localtime_r(&clock, tm);
    }

    inline struct tm* GmTime(struct tm* tm) const noexcept {
        time_t clock = Seconds();
        return GmTimeR(&clock, tm);
    }

    /**
     * Formats the instant using the UTC time zone, with microsecond precision.
     *
     * @returns An ISO 8601 formatted string, e.g. '2015-11-21T23:30:27.991669Z'.
     * @note Global Out method is defined to TInstant, so it can be written as text to IOutputStream.
     */
    TString ToString() const;

    /**
     * Formats the instant using the UTC time zone.
     *
     * @returns An RFC822 formatted string, e.g. 'Sun, 06 Nov 1994 08:49:37 GMT'.
     */
    TString ToRfc822String() const;

    /**
     * Formats the instant using the UTC time zone, with second precision.
     *
     * @returns An ISO 8601 formatted string, e.g. '2015-11-21T23:30:27Z'.
     */
    TString ToStringUpToSeconds() const;

    /**
     * Formats the instant using the system time zone, with microsecond precision.
     *
     * @returns An ISO 8601 / RFC 3339 formatted string,
     * e.g. '2015-11-22T04:30:27.991669+05:00'.
     */
    TString ToIsoStringLocal() const;

    /**
     * Formats the instant using the system time zone, with microsecond precision.
     *
     * @returns A semi-ISO 8601 formatted string with timezone without colon,
     * e.g. '2015-11-22T04:30:27.991669+0500'.
     */
    TString ToStringLocal() const;

    /**
     * Formats the instant using the system time zone.
     *
     * @returns An RFC822 formatted string, e.g. 'Sun, 06 Nov 1994 08:49:37 MSK'.
     */
    TString ToRfc822StringLocal() const;

    /**
     * Formats the instant using the system time zone, with second precision.
     *
     * @returns An ISO 8601 / RFC 3339 formatted string,
     * e.g. '2015-11-22T04:30:27+05:00'.
     */
    TString ToIsoStringLocalUpToSeconds() const;

    /**
     * Formats the instant using the system time zone, with second precision.
     *
     * @returns A semi-ISO 8601 formatted string with timezone without colon,
     * e.g. '2015-11-22T04:30:27+0500'.
     */
    TString ToStringLocalUpToSeconds() const;

    TString FormatLocalTime(const char* format) const noexcept;
    TString FormatGmTime(const char* format) const noexcept;

    /// See #TryParseIso8601.
    static TInstant ParseIso8601(TStringBuf);
    /// See #TryParseRfc822.
    static TInstant ParseRfc822(TStringBuf);
    /// See #TryParseHttp.
    static TInstant ParseHttp(TStringBuf);
    /// See #TryParseX509.
    static TInstant ParseX509Validity(TStringBuf);

    /// ISO 8601 Representation of Dates and Times
    ///
    /// @link https://www.iso.org/standard/40874.html Description of format.
    static bool TryParseIso8601(TStringBuf input, TInstant& instant);

    /// RFC 822 Date and Time specification
    ///
    /// @link https://tools.ietf.org/html/rfc822#section-5 Description of format.
    static bool TryParseRfc822(TStringBuf input, TInstant& instant);

    /// RFC 2616 3.3.1 Full Date
    ///
    /// @link https://tools.ietf.org/html/rfc2616#section-3.3.1 Description of format.
    static bool TryParseHttp(TStringBuf input, TInstant& instant);

    /// X.509 certificate validity time (see rfc5280 4.1.2.5.*)
    ///
    /// @link https://tools.ietf.org/html/rfc5280#section-4.1.2.5 Description of format.
    static bool TryParseX509(TStringBuf input, TInstant& instant);

    static TInstant ParseIso8601Deprecated(TStringBuf);
    static TInstant ParseRfc822Deprecated(TStringBuf);
    static TInstant ParseHttpDeprecated(TStringBuf);
    static TInstant ParseX509ValidityDeprecated(TStringBuf);

    static bool TryParseIso8601Deprecated(TStringBuf input, TInstant& instant);
    static bool TryParseRfc822Deprecated(TStringBuf input, TInstant& instant);
    static bool TryParseHttpDeprecated(TStringBuf input, TInstant& instant);
    static bool TryParseX509Deprecated(TStringBuf input, TInstant& instant);

    template <class T>
    inline TInstant& operator+=(const T& t) noexcept {
        return (*this = (*this + t));
    }

    template <class T>
    inline TInstant& operator-=(const T& t) noexcept {
        return (*this = (*this - t));
    }
};

Y_DECLARE_PODTYPE(TInstant);

template <>
struct THash<TInstant> {
    size_t operator()(const TInstant& key) const {
        return THash<TInstant::TValue>()(key.GetValue());
    }
};

namespace NPrivate {
    template <bool PrintUpToSeconds, bool iso>
    struct TPrintableLocalTime {
        TInstant MomentToPrint;

        constexpr explicit TPrintableLocalTime(TInstant momentToPrint)
            : MomentToPrint(momentToPrint)
        {
        }
    };
}

/** @name Helpers for printing local times to `IOutputStream`s.
 *        The FormatLocal* functions create an opaque object that, when written to
 *        a `IOutputStream`, outputs this instant as an ISO 8601 formatted string
 *        using the system time zone.
 *
 *  @note The only reason behind this set of functions is to avoid excessive
 *        allocations when you directly print the local time to a stream.
 *
 *        If you need something beyond just printing the value or your code
 *        is not performance-critical, feel free to use the corresponding
 *        TInstant::ToString*() functions.
 */
///@{
/// @see TInstant::ToIsoStringLocal()
::NPrivate::TPrintableLocalTime<false, true> FormatIsoLocal(TInstant instant);
/// @see TInstant::ToStringLocal()
::NPrivate::TPrintableLocalTime<false, false> FormatLocal(TInstant instant);
/// @see TInstant::ToIsoStringLocalUpToSeconds()
::NPrivate::TPrintableLocalTime<true, true> FormatIsoLocalUpToSeconds(TInstant instant);
/// @see TInstant::ToStringLocalUpToSeconds()
::NPrivate::TPrintableLocalTime<true, false> FormatLocalUpToSeconds(TInstant instant);
///@}

template <class S>
static constexpr bool operator<(const TTimeBase<S>& l, const TTimeBase<S>& r) noexcept {
    return l.GetValue() < r.GetValue();
}

template <class S>
static constexpr bool operator<=(const TTimeBase<S>& l, const TTimeBase<S>& r) noexcept {
    return l.GetValue() <= r.GetValue();
}

template <class S>
static constexpr bool operator==(const TTimeBase<S>& l, const TTimeBase<S>& r) noexcept {
    return l.GetValue() == r.GetValue();
}

template <class S>
static constexpr bool operator!=(const TTimeBase<S>& l, const TTimeBase<S>& r) noexcept {
    return l.GetValue() != r.GetValue();
}

template <class S>
static constexpr bool operator>(const TTimeBase<S>& l, const TTimeBase<S>& r) noexcept {
    return l.GetValue() > r.GetValue();
}

template <class S>
static constexpr bool operator>=(const TTimeBase<S>& l, const TTimeBase<S>& r) noexcept {
    return l.GetValue() >= r.GetValue();
}

namespace NDateTimeHelpers {
    template <typename T>
    static constexpr T SumWithSaturation(T a, T b) {
        static_assert(!std::numeric_limits<T>::is_signed, "expect !std::numeric_limits<T>::is_signed");

        return Max<T>() - a < b ? Max<T>() : a + b;
    }

    template <typename T>
    static constexpr T DiffWithSaturation(T a, T b) {
        static_assert(!std::numeric_limits<T>::is_signed, "expect !std::numeric_limits<T>::is_signed");

        return a < b ? 0 : a - b;
    }
}

constexpr TDuration operator-(const TInstant& l, const TInstant& r) noexcept {
    return TDuration::FromValue(::NDateTimeHelpers::DiffWithSaturation(l.GetValue(), r.GetValue()));
}

constexpr TInstant operator+(const TInstant& i, const TDuration& d) noexcept {
    return TInstant::FromValue(::NDateTimeHelpers::SumWithSaturation(i.GetValue(), d.GetValue()));
}

constexpr TInstant operator-(const TInstant& i, const TDuration& d) noexcept {
    return TInstant::FromValue(::NDateTimeHelpers::DiffWithSaturation(i.GetValue(), d.GetValue()));
}

constexpr TDuration operator-(const TDuration& l, const TDuration& r) noexcept {
    return TDuration::FromValue(::NDateTimeHelpers::DiffWithSaturation(l.GetValue(), r.GetValue()));
}

constexpr TDuration operator+(const TDuration& l, const TDuration& r) noexcept {
    return TDuration::FromValue(::NDateTimeHelpers::SumWithSaturation(l.GetValue(), r.GetValue()));
}

template <typename T, typename TRatio>
constexpr bool operator==(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return r.count() >= 0 && l == TDuration(r);
}

#if defined(__cpp_lib_three_way_comparison)

template <typename T, typename TRatio>
constexpr std::strong_ordering operator<=>(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    if (r.count() < 0) {
        return std::strong_ordering::greater;
    }
    return l.GetValue() <=> TDuration(r).GetValue();
}

#else

template <typename T, typename TRatio>
constexpr bool operator<(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return r.count() >= 0 && l < TDuration(r);
}

template <typename T, typename TRatio>
constexpr bool operator<=(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return r.count() >= 0 && l <= TDuration(r);
}

template <typename T, typename TRatio>
constexpr bool operator!=(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return !(l == r);
}

template <typename T, typename TRatio>
constexpr bool operator>(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return r.count() < 0 || l > TDuration(r);
}

template <typename T, typename TRatio>
constexpr bool operator>=(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return r.count() < 0 || l >= TDuration(r);
}

template <typename T, typename TRatio>
constexpr bool operator<(const std::chrono::duration<T, TRatio>& l, const TDuration& r) noexcept {
    return r > l;
}

template <typename T, typename TRatio>
constexpr bool operator<=(const std::chrono::duration<T, TRatio>& l, const TDuration& r) noexcept {
    return r >= l;
}

template <typename T, typename TRatio>
constexpr bool operator==(const std::chrono::duration<T, TRatio>& l, const TDuration& r) noexcept {
    return r == l;
}

template <typename T, typename TRatio>
constexpr bool operator!=(const std::chrono::duration<T, TRatio>& l, const TDuration& r) noexcept {
    return r != l;
}

template <typename T, typename TRatio>
constexpr bool operator>(const std::chrono::duration<T, TRatio>& l, const TDuration& r) noexcept {
    return r < l;
}

template <typename T, typename TRatio>
constexpr bool operator>=(const std::chrono::duration<T, TRatio>& l, const TDuration& r) noexcept {
    return r >= l;
}

#endif

template <typename T, typename TRatio>
constexpr TDuration operator+(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return r < r.zero() ? l - TDuration(-r) : l + TDuration(r);
}

template <typename T, typename TRatio>
constexpr TDuration operator+(const std::chrono::duration<T, TRatio>& l, const TDuration& r) noexcept {
    return r + l;
}

template <typename T, typename TRatio>
constexpr TDuration operator-(const TDuration& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return l + (-r);
}

template <typename T, typename TRatio>
constexpr TDuration operator-(const std::chrono::duration<T, TRatio>& l, const TDuration& r) noexcept {
    return TDuration(l) - r;
}

template <typename T, typename TRatio>
constexpr TInstant operator+(const TInstant& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return r < r.zero() ? l - TDuration(-r) : l + TDuration(r);
}

template <typename T, typename TRatio>
constexpr TInstant operator-(const TInstant& l, const std::chrono::duration<T, TRatio>& r) noexcept {
    return l + (-r);
}

template <class T>
inline TDuration operator*(TDuration d, T t) noexcept {
    Y_ASSERT(t >= T());
    Y_ASSERT(t == T() || Max<TDuration::TValue>() / t >= d.GetValue());
    return TDuration::FromValue(d.GetValue() * t);
}

template <>
inline TDuration operator*(TDuration d, double t) noexcept {
    Y_ASSERT(t >= 0 && MaxFloor<TDuration::TValue>() >= d.GetValue() * t);
    return TDuration::FromValue(d.GetValue() * t);
}

template <>
inline TDuration operator*(TDuration d, float t) noexcept {
    return d * static_cast<double>(t);
}

template <class T>
inline TDuration operator*(T t, TDuration d) noexcept {
    return d * t;
}

template <class T, std::enable_if_t<!std::is_same<TDuration, T>::value, int> = 0>
constexpr TDuration operator/(const TDuration& d, const T& t) noexcept {
    return TDuration::FromValue(d.GetValue() / t);
}

constexpr double operator/(const TDuration& x, const TDuration& y) noexcept {
    return static_cast<double>(x.GetValue()) / static_cast<double>(y.GetValue());
}

inline TInstant TDuration::ToDeadLine() const {
    return ToDeadLine(TInstant::Now());
}

constexpr TInstant TDuration::ToDeadLine(TInstant now) const {
    return now + *this;
}

void Sleep(TDuration duration);
void SleepUntil(TInstant instant);

static inline TInstant Now() noexcept {
    return TInstant::Now();
}

#ifdef _MSC_VER
    #pragma warning(pop)
#endif // _MSC_VER